Floaters and flashes

Description

Floaters are due to opaque material within the vitreous casting a shadow onto the retina. The vitreous naturally moves within the eye, and the shadows therefore appear to float about in the vision.

Often a normal finding, especially in myopic patients. New floaters of sudden onset often indicate separation of the vitreous from the retina (posterior vitreous detachment), usually a benign age-related change but capable of causing a retinal tear or detachment. 

Occasionally floaters may be due to bleeding into the vitreous (vitreous haemorrhage), inflammation within the vitreous (vitritis) or other material within the vitreous eg infection or tumour

Clinical Features

Benign floaters are bilateral, stable, do not impair vision and occur without any other symptoms.
Posterior vitreous detachment is characterised by new floaters of sudden onset in one eye, usually with associated flashing lights. There is often a large central floater that may appear like a spider or cobweb. Any reduction in vision particularly if like a curtain or shadow is likely to be due to retinal detachment.

Floaters from vitreous haemorrhage are also usually of sudden onset, may occur during or after physical exertion, are often dense and tend to settle downwards causing reduction particularly in the upper part of the vision. Flashing lights are not usually present. Vitreous haemorrhage may occur in association with PVD, retinal detachment, due to abnormal retinal blood vessels eg diabetes, or following trauma.

Floaters from intra-ocular inflammation or infection may be accompanied by pain or inflammation of the eye

Management

See ophthalmologist urgently if experiencing new onset floaters or flashing lights